[1] He was preconized as bishop by Pope Callixtus III on 3 October 1453 and took the oath of loyalty to Charles VII of France on 12 May 1454.
[1] On 11 June 1455 Pope Callixtus III named Bishop Longueil, along with Guillaume d'Estouteville, Archbishop of Rouen and Guillaume Chartier, Bishop of Paris, to a papal commission charged with posthumously retrying Joan of Arc.
[1] At the request of the King of France, Pope Callixtus III made Longueil a cardinal priest in the consistory of 17 December 1456.
[1] On 15 August 1461 he attended the coronation of Louis XI of France and shortly thereafter resigned as president of the Chambres des comptes.
[1] Louis XI revoked the Pragmatic Sanction of Bourges and Cardinal Longueil was part of a delegation (including Jean Jouffroy, Bishop of Arras) sent to inform the pope.
[1] As a result of his having left France, on 24 May 1463 the Conseil du Roi issued an order stopping all his benefices.